Generally speaking, the present invention relates to the field of the packaging of products inside cardboard boxes, for preparing and dispatching product orders. More particularly, this invention relates to a system for packaging products with immobilization by means of a shrink film covering all the products arranged inside a cardboard box and, after its shrinking, holding these products against one another and also against the base of the box. Even more especially, the invention relates to a packaging system that uses cardboard boxes comprising a base and a lateral band in cardboard and sheets in heat-shrinkable material attached, via one of their edges, in the region of the join between the base of the box and at least two sides of the lateral band of this box.